Mixing booze with energy drinks like Red Bull might be just as dangerous as drinking pre-made concoctions like Four Loko, which were recently banned by the feds following a string of college student hospitalizations and deaths, says a new study.

The cocktail of alcohol and Red Bull is more likely to trigger impulsive and often risky behavior than drinking traditional cocktails like a gin and tonic, according to the study by Cecile Marczinski, assistant professor of psychology at Northern Kentucky University and colleagues published today in the journal Alcoholism: Clinical & Experimental Research.

"Consumers should be aware that there are safety issues here with mixing energy drinks and alcohol," Marczinski said. "It may lead you to make poor decisions because you aren't really aware how intoxicated you are. You feel more awake, more alert."

Marczinski said the sedative effect of alcohol is negated by the caffeine and other stimulants, such as taurine, in energy drinks.

"Sedation or tiredness is a cue to stop drinking at the end of an evening. But mixing alcohol with an energy drink may lead you to drink more than you normally would," Marczinski said.

Classic cocktails like gin and tonic and rum and coke are increasingly being replaced by drinks like vodka-Red Bull and Jager Bombs -- Red Bull with a shot of spicy, 70-proof Jagermeister dropped in (glass and all).

The study follows a federal ban on the sale of alcoholic energy drinks like Four Loko, nicknamed "blackout in a can." The ban stemmed from a series of hospitalizations and even deaths among college students who downed the combo drinks to get wide-awake drunk.

The study by Marczinski and colleagues, which compared feelings of stimulation, sedation, and intoxication among 56 college students randomly assigned to drink vodka and Red Bull, vodka and soda, Red Bull alone or soda alone, adds to growing evidence that caffeine changes alcohol's effects on the body.

"From this study we really can conclude that these mixed beverages are pharmacologically distinct from just alcohol," Marczinski said. "They cause you to perceive intoxication levels differently even though you're equally impaired."

DIY Cocktails Untouched by Federal Ban

The ban on alcoholic energy drinks by the U.S. Food and Drug Administration enacted in January prohibits the sale of pre-mixed alcoholic energy drinks, often packaged in brightly-colored cans appealing to young, even underage drinkers. But the ban does not prevent the sale of ingredients used to create the dangerous cocktails in bars and at home.

"Those [pre-mixed] drinks are definitely problematic -- they contain a very large amount of alcohol and caffeine -- I think it was appropriate to pull them," Marczinski said. "But I think that the trend of mixing energy drinks and alcohol is probably not going away, and I'm not sure how you can regulate two separate products."

Dr. Mary-Claire O'Brien, associate professor of emergency medicine at Wake Forest University Baptist in Winston-Salem, N.C., said the ban was an important first step in curbing the dangerous practice of mixing alcohol with energy drinks.

"The rest of the responsibility goes to the state law enforcement agencies, to the consumers, to parents, to kids, to educators, to faculty at universities, to get the word out that this mixing is very dangerous behavior," she said.